Fire-protection coating

ABSTRACT

The invention relates to a fire-protection coating which forms an insulating layer and is based on substances which, in the event of a fire, form a foam layer and form carbon, on film-forming binders, on blowing agents, and on conventional auxiliaries and additives, which comprises a phosphinic salt of the formula (I) and/or a diphosphinic salt of the formula (II), and/or their polymers,  
                 
 
     where  
     R 1 , R 2  are identical or different and are C 1 -C 6 -alkyl, linear or branched and/or aryl;  
     R 3  is C 1 -C 10 -alkylene, linear or branched, C 6 -C 10 -arylene, -alkylarylene, or -arylalkylene;  
     M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, and/or a protonated nitrogen base;  
     m is from 1 to 4;  
     n is from 1 to 4;  
     x is from 1 to 4.

[0001] The invention relates to a fire-protection coating which forms an insulating layer and is based on substances which, in the event of a fire, form a foam layer and form carbon, on film-forming binders, on blowing agents, and on conventional auxiliaries and additives.

[0002] Fire-protection layers which form an insulating layer, also termed intumescent coatings, foam when exposed to the type of temperature occurring in the event of a fire, thus, by virtue of this foaming of the abovementioned fire-protection coating preventing, or at least inhibiting, the passage of heat to steel work, ceilings, walls, cables, pipes, and the like.

[0003] U.S. Pat. No. 4,965,296 A1 describes a flame-retardant material composed of a flame-retardant coating material and of an electrically conductive material. The flame-retardant coating material here is composed of substances which form foam and form carbon, of a compound which evolves gas, of a film-forming binder, and of appropriate solvents. Other conventional ingredients may be present if desired.

[0004] U.S. Pat. No. 4,879,320 describes a similar flame-retardant composition to which, instead of a conductive material, a ceramic fiber material has been added.

[0005] U.S. Pat. No. 5,225,464 describes an aqueous intumescent formulation based on a reaction product of phosphoric acid, melamine and monoammonium phosphate. This formulation with pentaerythritol, chlorinated hydrocarbons, and other compounds, in particular polyvinyl acetate, is intended to provide an improved intumescent coating material.

[0006] DE 42 18 184 A1 describes an aqueous binder mixture composed of an aqueous solution and/or dispersion of a combination of a) at least one NCO prepolymer which has capped isocyanate groups and has urethane groups and, in the presence of component b), is dispersible and/or soluble in water, and b) a polyamine component composed of at least one (cyclo)aliphatic polyamine having at least two primary and/or secondary amino groups.

[0007] Finally, DE 43 43 668 describes expandable, flame-retardant coating compositions composed at least of from 4 to 25% by weight of a film-forming binder, from 10 to 40% by weight of ammonium polyphosphate, from 8 to 40% by weight of at least one substance which carbonizes on exposure to heat, from 6 to 25% by weight of a blowing agent, from 0 to 5% by weight of dispersing agents, and from 0 to 25% by weight of fillers.

[0008] The aim of the abovementioned fire-protection coatings of the prior art is to achieve maximum fire-resistance times, using minimum application quantities.

[0009] An overall disadvantage of the abovementioned fire-protection coatings is that the foam structures formed in the event of a fire do not permit an improvement in insulating action, and that the reaction does not start until temperatures T≧180° C. have been reached.

[0010] An object of the invention which follows is therefore to provide fire-protection coatings which achieve longer fire-resistance times for the same application quantity, or achieve fire-resistance times identical with those of the prior art with a reduced application quantity.

[0011] It is intended that the reaction start at temperatures T<180° C.

[0012] This object has been achieved by way of a fire-protection coating which forms an insulating layer as described at the outset, which comprises a phosphinic salt of the formula (I) and/or a diphosphinic salt of the formula (II), and/or their polymers,

[0013] where

[0014] R¹, R² are identical or different and are C₁-C₆-alkyl, linear or branched and/or aryl;

[0015] R³ is C₁-C₁₀-alkylene, linear or branched, C₆-C₁₀-arylene, -alkylarylene, or -arylalkylene;

[0016] M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, and/or a protonated nitrogen base;

[0017] m is from 1 to 4;

[0018] n is from 1 to 4;

[0019] x is from 1 to 4.

[0020] M is preferably calcium, aluminium or zinc.

[0021] The protonated nitrogen bases are preferably the protonated bases of ammonia, melamine, or triethanolamine, in particular NH₄₊.

[0022] R¹, R², which are identical or different, are preferably C₁-C₆-alkyl, linear or branched, and/or phenyl.

[0023] R¹ and R², which are identical or different, are particularly preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl and/or phenyl.

[0024] R³ is preferably methylene, ethylene, n-propylene, isopropylene, n-butylene, tert-butylene, n-pentylene, n-octylene or n-dodecylene; phenylene or naphthylene; methylphenylene, ethylphenylene, tert-butylphenylene, methylnaphthylene, ethylnaphthylene or tert-butylnaphthylene; phenylmethylene, phenylethylene, phenylpropylene or phenylbutylene.

[0025] The fire-protection coating which forms an insulating layer preferably comprises

[0026] from 5 to 30 parts by weight of film-forming binder,

[0027] from 10 to 50 parts by weight of substance which forms a foam layer,

[0028] from 5 to 25 parts by weight of a substance which forms carbon,

[0029] from 5 to 25 parts by weight of a blowing agent, and

[0030] from 10 to 50 parts by weight of conventional auxiliaries and additives, and

[0031] from 1 to 10 parts by weight of phsophinic salt of the formula (I)

[0032] and/or a diphosphinic salt of the formula (II), and/or their polymers.

[0033] The fire-protection coating which forms an insulating layer particularly preferably comprises

[0034] from 10 to 25 parts by weight of film-forming binder,

[0035] from 15 to 40 parts by weight of substance which forms a foam layer,

[0036] from 7 to 15 parts by weight of a substance which forms carbon,

[0037] from 7 to 15 parts by weight of a blowing agent, and

[0038] from 20 to 40 parts by weight of conventional auxiliaries and additives, and

[0039] from 2 to 5 parts by weight of phosophinic salt of the formula (I) and/or a diphosphinic salt of the formula (II), and/or their polymers.

[0040] Preference is given to a fire-protection coating which forms an insulating layer in which the film-forming binders present comprise

[0041] homopolymers based on vinyl acetate,

[0042] copolymers based on vinyl acetate, ethylene, and vinyl chloride,

[0043] copolymers based on vinyl acetate and on the vinyl ester of a long-chain, branched carboxylic acid,

[0044] copolymers based on vinyl acetate and di-n-butyl malate,

[0045] copolymers based on vinyl acetate and esters of acrylic acid,

[0046] copolymers based on styrene and esters of acrylic acid, and/or

[0047] copolymers based on esters of acrylic acid,

[0048] vinyltoluenel/acrylol copolymer,

[0049] styrene/acrylate polymers,

[0050] vinyl/acrylate copolymers,

[0051] self-crosslinking polyurethane dispersions.

[0052] Preference is given to a fire-protection coating which forms an insulating layer and in which the foam-forming substances present comprise ammonium salts of phosphoric acids and/or polyphosphoric acids.

[0053] Preference is given to a fire-protection coating which forms an insulating layer and in which the carbon-forming substances present comprise carbohydrates.

[0054] Carbohydrates whose use is preferred are pentaerythritol, dipentaerythritol, tripentaerythritol and/or polycondensates of pentaerythritol.

[0055] Preference is given to a fire-protection coating which forms an insulating layer and in which the blowing agents present comprise melamine and/or guanidine, or else their salts, and/or dicyandiamides.

[0056] The melamine salts preferably comprise melamine phosphate, melamine cyanurate, melamine borate, melamine silicate, and the guanidine salt preferably comprises guanidine phosphate.

[0057] The fire-protection coating which forms an insulating layer also preferably comprises melamine polyphosphate.

[0058] Preference is given to a fire-protection coating which forms an insulating layer and in which the auxiliaries and additives present comprise glass fibers, mineral fibers, kaolin, talc, aluminum oxide, aluminum hydroxide, magnesium hydroxide, precipitated silicas, silicates, and/or pulverized celluloses.

[0059] The inventive fire-protection coating (intumescent coating) is used in the form of a paint which can be applied by brush, spray, or roller, to protect various substrates, preferably steel, wood, electrical cables, and pipes.

[0060] In the examples below, intumescent coatings are prepared, and applied to standard steel sheets, and their effectiveness is determined. The test for insulating capability was based on DIN 4102.

[0061] The following products were used in the examples:

[0062] ®Pliolite (Solid) (Goodyear, France)

[0063] This is a newtonian, thermoplastic resin based on vinyltoluene-acrylate copolymer.

[0064] ®Mowilith DM230

[0065] This is a plasticizer-free, aqueous copolymer dispersion of strength about 50%, composed of vinyl acetate and Versatic ester.

[0066] ®Exolit AP 462 (Clariant GmbH, Frankfurt am Main)

[0067] This is a microencapsulated ammonium polyphosphate based on ®Exolit AP 422, prepared by the process of EP-B-0 180 795, and comprising about 10% by weight of encapsulating material, composed of a cured melamine-formaldehyde resin.

[0068] ®Exolit AP 422 (Clariant GmbH, Frankfurt am Main) is a free-flowing, pulverulent, low-water-solubility ammonium polyphosphate of the formula (NH₄PO₃), where n=20 to 1000, in particular from 500 to 1000. The proportion of the particles whose particle size is smaller than 45 μm is more than 99%.

EXAMPLE 1 Comparison

[0069] The following substances were mixed with one another and then appropriately applied to the sheet to be tested:

[0070] 38 parts by weight of ®Exolit AP 462

[0071] 10 parts by weight of ®Pliolite (Solid)

[0072] 8 parts by weight of melamine

[0073] 8 parts by weight of dipentaerythritol

[0074] 8 parts by weight of titanium dioxide

[0075] thickeners, plasticizers and solvents to 100 parts by weight.

[0076] The fire test on the coated sheet, based on DIN 4102, gave a reaction starting temperature T=180° C., the application quantity being 100%.

EXAMPLE 2 Inventive

[0077] The following substances were mixed with one another and then appropriately applied to the sheet to be tested:

[0078] 32 parts by weight of ®Exolit AP 462

[0079] 10 parts by weight of ®Pliolite (Solid)

[0080] 13 parts by weight of melamine

[0081] 8 parts by weight of dipentaerythritol

[0082] 8 parts by weight of titanium dioxide

[0083] 5 parts by weight of aluminum diethylphosphinate

[0084] thickeners, plasticizers and solvents to 100 parts by weight.

[0085] The fire test on the coated sheet, based on DIN 4102, gave a reaction starting temperature T=100° C., the application quantity being 100%.

EXAMPLE 3 Comparison

[0086] The following substances were mixed with one another and then appropriately applied to the sheet to be tested:

[0087] 30 parts by weight of ®Exolit AP 422

[0088] 22 parts by weight of ®Mowilith DM230

[0089] 19 parts by weight of melamine

[0090] 13 parts by weight of pentaerythritol

[0091] 5 parts by weight of titanium dioxide

[0092] thickeners, fillers, water, dispersants and preservatives to 100 parts by weight.

[0093] The fire test on the coated sheet, based on DIN 4102, gave a fire-resistance time of 86 minutes, the application quantity being 100%.

EXAMPLE 4 Inventive

[0094] The following substances were mixed with one another and then appropriately applied to the sheet to be tested:

[0095] 18 parts by weight of ®Exolit AP 422

[0096] 22 parts by weight of ®Mowilith DM230

[0097] 30 parts by weight of melamine

[0098] 13 parts by weight of pentaerythritol

[0099] 5 parts by weight of titanium dioxide

[0100] 2 parts by weight of aluminum diethylphosphinate

[0101] thickeners, fillers, water, dispersants and preservatives to 100 parts by weight.

[0102] The fire test on the coated sheet, based on DIN 4102 gave a fire-resistance time of 87 minutes, the application quantity being 80%.

[0103] Using the inventive fire-protection coating, the fire-resistance time can be increased advantageously, or the application quantity can be reduced advantageously. There is also a marked reduction in reaction start temperature. 

1. A fire-protection coating which forms an insulating layer and is based on substances which, in the event of a fire, form a foam layer and form carbon, on film-forming binders, on blowing agents, and on conventional auxiliaries and additives, which comprises a phosphinic salt of the formula (I) and/or a diphosphinic salt of the formula (II), and/or their polymers,

where R¹, R² are identical or different and are C₁-C₆-alkyl, linear or branched and/or aryl; R³ is C₁-C₁₀-alkylene, linear or branched, C₆-C₁₀-arylene, -alkylarylene, or -arylalkylene; M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, and/or a protonated nitrogen base; m is from 1 to 4; n is from 1 to 4; x is from 1 to
 4. 2. The fire-protection coating which forms an insulating layer, as claimed in claim 1, wherein M is calcium, aluminum, or zinc.
 3. The fire-protection coating which forms an insulating layer, as claimed in claim 1 or 2, wherein R¹ and R² are identical or different and are C₁-C₆-alkyl, linear or branched, and/or phenyl.
 4. The fire-protection coating which forms an insulating layer, as claimed in one or more of claims 1 to 3, wherein R¹ and R² are identical or different and are methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl and/or phenyl.
 5. The fire-protection coating which forms an insulating layer, as claimed in one or more of claims 1 to 4, wherein R³ is methylene, ethylene, n-propylene, isopropylene, n-butylene, tert-butylene, n-pentylene, n-octylene or n-dodecylene; phenylene or naphthylene; methylphenylene, ethylphenylene, tert-butylphenylene, methylnaphthylene, ethylnaphthylene or tert-butylnaphthylene; phenylmethylene, phenylethylene, phenylpropylene or phenylbutylene.
 6. The fire-protection coating which forms an insulating layer, as claimed in one or more of claims 1 to 5, which comprises from 5 to 30 parts by weight of film-forming binder, from 10 to 50 parts by weight of substance which forms a foam layer, from 5 to 25 parts by weight of a substance which forms carbon, from 5 to 25 parts by weight of a blowing agent, and from 10 to 50 parts by weight of conventional auxiliaries and additives, and from 1 to 10 parts by weight of aluminium diethylphosphinate.
 7. The fire-protection coating which forms an insulating layer, as claimed in one or more of claims 1 to 6, which comprises from 10 to 25 parts by weight of film-forming binder, from 15 to 40 parts by weight of substance which forms a foam layer, from 7 to 15 parts by weight of a substance which forms carbon, from 7 to 15 parts by weight of a blowing agent, and from 20 to 40 parts by weight of conventional auxiliaries and additives, and from 2 to 5 parts by weight of aluminium diethylphosphinate.
 8. The fire-protection coating which forms an insulating layer, as claimed in one or more of claims 1 to 7, wherein the film-forming binders present comprise homopolymers based on vinyl acetate, copolymers based on vinyl acetate, ethylene, and vinyl chloride, copolymers based on vinyl acetate and on the vinyl ester of a long-chain, branched carboxylic acid, copolymers based on vinyl acetate and di-n-butyl malate, copolymers based on vinyl acetate and esters of acrylic acid, copolymers based on styrene and esters of acrylic acid, and/or copolymers based on esters of acrylic acid, vinyltoluenel/acrylol copolymer, styrene/acrylate polymers, vinyl/acrylate copolymers, self-crosslinking polyurethane dispersions
 9. The fire-protection coating which forms an insulating layer, as claimed in one or more of claims 1 to 8, wherein the foam-forming substances present comprise ammonium salts of phosphoric acids and/or polyphosphoric acids.
 10. The fire-protection coating which forms an insulating layer, as claimed in one or more of claims 1 to 9, wherein the carbon-forming substances present comprise carbohydrates.
 11. The fire-protection coating which forms an insulating layer, as claimed in claim 7, wherein the carbohydrates used comprise pentaerythritol, dipentaerythritol, tripentaerythritol and/or polycondensates of pentaerythritol.
 12. The fire-protection coating which forms an insulating layer, as claimed in one or more of claims 1 to 11, wherein the auxiliaries and additives present comprise glass fibers, mineral fibers, kaolin, talc, aluminum oxide, aluminum hydroxide, magnesium hydroxide, precipitated silicas, silicates and/or pulverulent celluloses.
 13. The fire-protection coating which forms an insulating layer, as claimed in one or more of claims 1 to 12, wherein the blowing agents present comprise melamine and/or guanidine, or else their salts, and/or dicyandiamides.
 14. The fire-protection coating which forms an insulating layer, as claimed in claim 13, wherein the melamine salts used comprise melamine phosphate, melamine cyanurate, melamine borate, melamine silicate, and the guanidine salt used comprises guanidine phosphate.
 15. The fire-protection coating which forms an insulating layer, as claimed in one or more of claims 1 to 14, which also comprises melamine polyphosphate. 